Skip to main content

Full text of "Text Book Of Mechanical Engineering"

See other formats


Erecting the Engine.                         269

of the square, up to the bearing faces (shewn by curved arrows).
Adjust bearings till (i) straightedge touches measuring lath;
(2) square touches string along its whole length; (3) face of
brasses is lineable with measure of straightedge j and (4) straight-
edge exactly touches bearing brass throughout its length. Then
mark the bearing stud holes through upon the bed, and do the
same with the cylinder holes.

The Slide Bar Bracket must be placed with reference to slide
bar length. It is wisest, therefore, to temporarily fasten the front
cylinder cover and the two bottom slide bars. When all are
together, as at dy the bracket is set to central position by squaring
up from its top surface to the string, and the stud holes traced
through.

The Valve-Spindle Guide Bracket must also be true with
regard to the spindles, so these are put through the stuffing boxes
wid the bracket, and the latter adjusted by measurement from
cyliader face on the one hand, *, and from the string on tfie
other hand, using blocked-up laths at h. If the spindles do not
slide truly, a slight readjustment can be made. Examine also for
appearance regarding seating, then scribe the stud holes. The
governor bracket comes to the Erector fitted up entirely with
governors, links, and pullies. Set up in approximate position,
and measure the distances j from the boss faces to the string,
these being the most important; adjust to these, and also to
distances from cylinder face (<?) and crank bearing (K)J, Then
test, by measurements at K and G, for parallelism of pulley
spindle, and mark off the holes.

The holding-down bolts are lastly marked, all the parts re-
moved, the circles centre-punched, and the Bed Plate either taken
to a racial drill, or drilled by ratchet brace, the former being
preferable. Tap all the stud holes and insert studs; then return
the bed to its erecting position, which need not this time be
level, the main adjustments having been made. And now the
various pieces are to be put in place in the order we sWl mention.
First the Cylinder is bolted down, and the Front Cover put on,
the Piston Inserted, and the Rod passed through; then the Slide
Bar Bracket, and the Bottom Slide Bars. The Bearings come
next, and when fixed have the Crank Shaft laid upon them, with